The Korean Journal of Environmental Agriculture is an official publication of the Korean Society of Environmental Agriculture. It is published quarterly a year, March 31, June 30, September 30, and December 31, and distributed to more than 700 members including individuals and institutions. The abbreviated title is ‘Korean J. Environ. Agric.’ The journal was launched on June 30 in 1982, the Print ISSN was issued on October 30, 1992 (Volume 11, No. 2) while the Online ISSN was issued on December 31, 2010 (Volume 29, No. 4). Whole document of a part of the articles in this journal are listed in the Google Scholar, Korea Citation Index (KCI) and ScienceCentral. The full text is freely available from http://www.korseaj.org.

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BACKGROUND:

Tillage systems and fertilization play an important role in crop growth and soil improvement. This study was conducted to determine the effects of tillage and fertilization on themicrobial biomass Cand dehydrogenase activity of soils in a field under cultivation of soybean.

METHODS AND RESULTS:

An experimental plot, located in the temperate climate zone,was composed of two main sectors that were no-tillage (NT) and conventional tillage (CT), and they were subdivided into four plots, respectively, in accordance with types of fertilizers (non fertilizer, chemical fertilizer, hairy vetch, and liquid pig manure).Microbial biomass C and dehydrogenase activity were evaluated from May to July in 2016. The microbial biomass C and dehydrogenase activity of NT soils were significantly higher than those of CT in all fertilizer treatments, and they were further increased in hairy vetch treatment than the other fertilizer treatments in bothNTand CT. The dehydrogenase activity was closely related to microbial biomass C.

CONCLUSION:

It is concluded that application of green manure combined with no-tillage can provide viable management practices for enhancing microbial properties of soil.

BACKGROUND:

To evaluate residues of environmentally concerned pesticides in water system, this monitoring was conducted over three rivers. The residual characteristics and discharging condition of these residues onwater system was investigated.

METHODS AND RESULTS:

Total twenty nine sampling sites were selected through main streams and branch streams of Keum, Mangyung and Dongjin rivers, and the water samples from them were regularly collected one month interval, especially biweekly fromMay toAugust in 2002. Of the pesticides monitored, six fungicides which include hexaconazole, isoprothiolane and iprobenfos were detectedwith frequencies of 0.3-50.9%and in their residue level of 0.1-4.7 g/L. Sixteen μ insecticides which include nine organophosphoruses, three carbamates, endosulfan, cypermethrin, buprofezin and fipronil were detected with frequencies of 0.3-32.5% and in their residue level of 0.01-2.8 μg/L. Nine herbicides which include alachlor molinate, anilofos, butachlor, dimepiperate, metolachlor, oxadiazon, pretilachlor and thiobencarbwere detectedwith frequencies of 0.8-22.9% and in their residue level of 0.01-9.07 μg/L.

CONCLUSION:

Detection frequencies and residue levels of insecticides and herbicides were the highest in waters sampled inMay and June. Almost pesticides detectedwere for the paddy rice and their residue levels were very low to compare with standard values.

BACKGROUND:

RNAinterference (RNAi) eliminates or decreases gene expression by disrupting the target mRNA or by interfering with translation. Recently, RNAi technique was applied to generate new crop traits which provide protection against pests. To establish the environmental risk assessment protocol of RNAi LMO in lab scale, we developed dsRNA expression systemusing E. coli and tested acute oral toxicity assay to honey.

METHOD AND RESULTS:

The dsRNA expression vector, L4440, was chosen and cloned 240 bp of Snf7 and GFP gene fragment. To develop the maximum dsRNA induction condition in E. coli, we tested induction time, temperature and IPTG concentration inmedia. To estimate the risk assessment of dsRNA to honey bee, it has been selected and cultured with dsRNA supplement for 48 hours according to OECD guideline. As a result, the optimum condition of dsRNA induction was 37℃, 4 hours and 0.4 mM IPTG concentration and the difference between Snf7 and GFP dsRNA molecules from E. coli was not significant in survival and behavior to honey bee. Furthermore, blast search results indicated that effective match of predicted dsRNA fragments were not existed in honey bee genome.

CONCLUSION:

In this study,we developed and tested the acute oral toxicity of dsRNA using E. coli expression system to honey bee.

BACKGROUND:

Globally, mulberry (Morus sp.) is exploited for feeding leaf to silkworms in order to obtain silk fiber or for animal feedstock production. Also, mulberry fruit is known to a by-product that was produced from mulberry tree after harvesting leaves for silkworm rearing, as a yield and consumption of mulberry fruit was increased, it has been fixing to a new income crop.Mulberry leaves and fruits are used for the health benefits of human beings. Mulberry contains various bioactive components, such as alkaloids and flavonoids. Mulberry flavonoids are an important part of the diet because of their effects on human nutrition. The flavonoids in mulberry leaf and fruit of ‘Suhyang’(Morus alba L.) were determined.

METHODSANDRESULTS:

Flavonoids formulberry leaf and fruit of ‘Suhyang’ were analysed using ultrahigh performance liquid chromatography coupled with diode array detection and quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF/MS) technique. An UPLC-DAD-QTOF/MS system was used, and identification of mulberry leaves constituentswas carried out on the basis of the complementary information obtained fromLC spectra, MS ions, and MS/MS fragments. The mulberry leaf (16 flavonoids) and fruit (9 flavonoids) were isolated and analyzed from Suhyang using UPLC-DAD-QTOF/MS chromatogram. To the best of our knowledge, Quercetin 3-O-(6''-O-malonyl) glucoside and quercetin 3-O-rutinoside (rutin) was detected on the highest content in leaf and fruit, respectively and further researchwill be devoted to evaluate their biological activity.

CONCLUSION:

Obtaining information about the concentration of functional materials inmulberry leaves could contribute to the development and promotion of processed, functional products and offer possible industrial use of ‘Suhyang’, holding promises to enhance the overall profitability of sericulture.